I always thought "loo" came from "waterloo" from "water closet"; much in the same way as words like "titfer" and "take a butcher's"....

"maisonette", in England, is a semi-detached or terraced house where the ground floor is one apartment and the upper floor(s) are another. There is no communal stairwell; each upper apartment has its own front door at street level and its own private stairs. Some were built this way; others converted from a large house. So the word is well-known.

1983, Lawrence Durrell, Sebastian, Faber & Faber 2004 (Avignon Quintet), p. 1057:

That is the little bit of essential information which enables us to complete our devoir

Just astounding how much French there is in English!

we also have "maisonette" and "manor" in English, both from Fr.

"Nous devons écrire un contrat pour la maison."
= we endeavour to scribe a contract for the mansion. (endeavour

"Again, in romance and germanic tongues it is often possible to guess at meanings: that just doesn't seem to work once one moves east"
Not hard to link "Schaf" with "sheep" or come up with "ewe" for "owca" (polish=sheep)
but moving east, hard to guess that "domba" (Indonesian) means the same.
My own experience is that it takes three times as long for an "Asian" student to learn everyday English vocabulary, compared to a European. The reverse is also true. Finnish, Hungarian (or worse still tonal tongues like Chinese, Vietnamese, Thai) are much harder for us than easy-to-guess Italian or Danish.
French people can often write quite passable English sans difficulte', whereas it is rare indeed for ,say, a Korean to achieve the same level - the hurdles, the idiom, the way of expressing ideas are too "European" and far-adrift from their own.

And frith and froth be with you too.

" it's a froth to behold ..."
I only found froth to mean bubbles in the dictionary.
There are however "frover" and "frother" as doing-words, which might bring more joy.

The point about French is that one gets past the basics the word-stock is often the similar - for at least 8000 words. More if you are Spanish, very little if you are Germanic.
For an English speaker, German starts off better, but the business and academic word-stock is harder to recall. "contract" in German -> er, ..Betrag. no...Beitrag...ah Vertrag. French so much easier at this level.
Again, romance and germanic tongues it is often possible to guess at meanings: that just doesn't seem to work once one moves east.
It is important to remember that out-and-out Anglishers would have nearly half of a school-leaver's word-stock ripped out and replaced. I don't think that will go down truly well.

I think "sans" is in the English dictionary - used by Shakespear - sans teeth ....

Never ceases to amaze me how close French is to English, how easy to read sans wordbook.

Had the Lousiana purchase fallen thru, les Americains would be speaking French, and so would we all.

(Or had Arpad got to America.... or Columbus landed further north.....)